Đáp án + Giải thích các bước giải:
`a, (2/5)^x = 4/25`
`<=> (2/5)^x = (2/5)^2`
`=> x=2`
`Vậy `x=2`
`b, (x-1/3)^3 = -8/27`
`<=> (x-1/3)^3 = (-2/3)^3`
`<=> x-1/3 = -2/3`
`<=> x=-1/3`
`c, (5/6 -x)^2 = 1/4`
`<=> (5/6 -x)^2 = (1/2)^2`
`TH1:`
`=> 5/6 - x =1/2`
`<=> x=1/3`
`TH2:`
`=> 5/6 - x = -1/2`
`<=> x = 4/3`
Vậy `x=1/3;x=4/3`
`d, 4/25 -|x+1/2| = (-2/5)^2`
`<=> |x+1/2|=0`
`=> x+1/2=0`
`<=> x=-1/2`
Vậy `x=-1/2`
